Control system for photocomposing machines



June 4, 1940. A. 'r. KOPPE 2,203,094

CONTROL SYSTEM FOR PHOTOCOHPOSING CHIEFS Filed Aug. 22, 1956 11 Shets-Sheet 1 INVENTOR Amp Zfippe ATTORNEYS A. T PPE,

June 4 1940.

CONTROL SYSTEM FOR PHOTOCOMPOSING IACHINES Filed Aug. 22, 1936 11 Sheets-Sheet 2 oR Alexawr I We WI 9 M ATTORNEYS June 4, 1940. A. 'r. KOPPE CONTROL SYSTEM FOR PHOTOCOMPOSING MACHINES Filed Aug. 22, 1936 ll Sheets-Sheet 3 rjlflfuppe AZa w nd/ Q PM ATTORNEYS June 4, 1940. A. T. KOPPE 2,203,094

CONTROL SYSTEM FOR PHOTOCOMPOSING MACHINES Filed Aug. 22, 1936 11 Sheets-Sheet 4 Li? I 7 INVENTOR Alexander 1 15672 20 W 9 M ATTOR EYS June 4, 40- A. T. KOPPE 2,203,094

CONTROL SYSTEM FOR PHOTOCOMPOSING MACHINES Filed Aug. 22, 1936 ll Sheets-Sheet 5 INVENTOR Agrmuiar 1750,0 06 W, QM

ATTOR EYS June 4, 1940. KQPPE 2,203,094

CONTROL SYSTEM FOR PHOTOGOMPOSING MACHINES Filed Aug. 22, 1936 11 Sheets-Sheet 6 w INVENTOR 15 WM M ATTORNEYS A. T. KOPPE 2,203,094

CONTROL SYSTEM FOR PHOTOCOMPOSING MACHINES Filed Aug. 22, 1936 ll Sheets-Sheet 7 June 4, 1940.

June 4, 1940. A. T. KOPPE CONTROL SYSTEM FOR PHOTOCOMPOSING IACHINES Filed Aug. 22, 1936 11 Sheets-Sheet 9 June 4, 1940. A. 1'. KOPPE CONTROL SYSTEM FOR PHOTOCOMPOSING IIACHINES Filed Aug. 22, 1936 11 Shets-Sheet 1O INVENTOR Alexander Z'fi'aype (Mfiaf w ATTOR E35 cmssxv .5 g NN S km W; F: GE

June 4, 1940. A. 'r. KOF'PE CONTROL SYSTEM FOR PHOTOCOMPOSING MACHINES Filed Aug. 22, 1936 ll Sheets-Sheet 11 I INVENTOR Ale'xardel' fll op ve Patented June 4, 1940 UNITED STATES PATENT OFFICE CONTROL SYSTEM FOR PHOTOCOMI'OSING MACHINES Application August 22,

14 Claims.

My invention relates to a control system for photocomposing machines.

My invention has particular reference to system for controlling movement, in a desired manner, of various operating parts of a photocomposing machine.

More particularly, my invention relates to a control system adapted, in part, to be rendered ineffective during those periods when the printing plate is held in printing relation with respect to the sensitized suriace.

Various other objects, advantages and characteristics of my invention will become apparent from the following detailed description.

My invention resides in the photocomposing art, control system for a photocomposing machine, features, combinations and arrangements of the character hereinafter described and claimed.

My invention relates to a control system adapted to be utilized, for example, in connection with a photocomposing machine of the character disclosed in U. S. Letters Patent No. 2,174,726.

For an understanding of my invention and for an illustration of one of the many forms thereof, reference is to be had to the accompanying drawings, in which:

Figure 1 is an elevational view of my novel photocomposing machine as viewed from the front;

Fig. 2 is a transverse, vertical sectional view, partly in elevation and with parts Omitted, taken substantially centrally of the machine shown in Fig. 1;

Fig. 3 is an enlarged, fragmentary view, partly in section, showing one of the switches as constructed in accordance with my invention;

Fig. 4 is a horizontal sectional view, partly in plan and with parts omitted, this view being taken centrally of the machine shown in Fig. 1;

Fig. 5 is an enlarged, fragmentary view, partly in section, showing the timer mechanism of my invention;

Fig. 6 is an enlarged, horizontal sectional view, partly in plan and with parts omitted, of the right side of the machine shown in Fig. 1;

Fig. 7 is an enlarged sectional view showing a plurality of the meshing pinions of Fig. 4;

Fig. 8 is a fragmentary plan view of a part of the arrangement shown in Fig. 7;

Fig. 9 is an enlarged, horizontal sectional view, partly in plan and with parts omitted, of the left side of the machine shown in Fig. 1;

Fig. 10 is an enlarged, fragmentary view, partly 1936, Serial No. 97,432

in section, showing the vacuum valve arrangement of my invention;

Fig. 11 is a side elevational view, taken substantially on the line ll-l i of Fig. 9;

Fig. 12 is a side elevational view corresponding with Fig. 11 but showing the parts in difierent positions, respectively;

Fig. 13 is an elevational view, with parts omitted, showing the rear of my novel photocomposing machines;

Fig. 14 is a perspective view showing the shifting mechanism for shifting the backboard toward and from printing position;

Fig. 15 is a perspective view corresponding with Fig. 14 but showing a difierent position of some of the parts;

Fig. 16 is a semi-diagrammatic, perspective view, with parts omitted, of the photocomposing machine of my invention;

Fig. 17 is a diagrammatic view principally showing the control circuits of the electrical motor system; and

Fig. 18 is a diagrammatic view principally showing the control circuits of the timer system.

Inasmuch as the particular form of control system herein disclosed is adapted for use with a photocomposing machine of the character disclosed in U. S. Letters Patent No. 2,174,726, I have deemed it desirable to include as apart of this application a substantial part of the disclosure forming a part of U. S. Letters Patent Thus, referring to Fig. 1, there is shown a hollow base I which is adapted to occupy a fixed position on a floor or other suitable supporting surface. As illustrated, the base i comprises oppositely extending wing sections la, la, these being utilizable in the manner hereinafter described. Upstanding from said base I are a pair of standards 2, 2a, these standards being vertically disposed in parallel relation and suitably secured to the base I, as by the bolts 3. Suitably fastened in fixed position to the top surfaces of the standards 2, 2a is a horizontal bar 4' formed from non-flexible metallic material. This bar 4 extends equal distances beyond each of the standards 2, 2a and each projecting section of said bar 4 has an angle member 5 suitably secured thereto. As clearly shown in Fig. 1, a vertical wing member 6 is suitably secured, as by screws or bolts, to each angle member 5, to the adjacent base wing section la which is disposed therebelow, and to the adjacent standard 2 or 2a as the case may be. It results, therefore, with an arrangement of the character described, that the wings 6 are vertically disposed in the same vertical plane and that they form fixed extensions of the base I. Preferably although not necessarily, each of the wings 6 is formed from a sheet of wood which is covered by suitable sheet metal shaped to form smooth, flat inner and outer surfaces.

As shown in Figs. 1 and 2, each of the standards 2, 2a has a vertical track member l suitably se cured thereto in fixed position, the top surfaces of said track members I being connected together by a transversely, horizontal member ii. The track members i are disposed in the same verti= cal plane, this plane being parallel with respect to the plane of the wings 6 and closely adjacent thereto.

Vertically disposed immediately adjacent each of the track members l is a jack screw 9, these jack screws being rotatably mounted in upper and lower bearings 9o formed in projecting sections of the respective standards 2, 2o.

Coactable with each or the jack screws it is a traveling nut to, each nut it carrying a bracizet arm 6 I, Fig. 21, the bracket arms l i being secured in. suitable manner to the respective slide e bers 52 which slidably engage the track members I, respectively, Fig. 5, the hereinafter described frame F also coacting with said tract: members l in. a guiding sense. As well understood in the art, the slide members iii coact with their reepective track members to prevent horizontal play while providing for the desired freedom oi movement between coacting parts. Each of the slide members it, then, is positioned adjacent one of the jack screws 9 and said slide members it are bolted or otherwise suitably secured to the opposite vertical sides, respectively, of a supporting frame F having a rectangular opening.

This supporting frame L is adapted to move either upwardly or downwardly in the space between the two track members i]. As shown in Figs. 1 and 2-, upper and lower curtains l3 and M are connected to the respective upper and lower sides of the supporting frame F. The upper curtain ill is wound upon a horizontal roller 05 supported by end brackets it carried by and depending from the bar 0, Fig. 2, these end braclz= ets also supporting a horizontal idler roller il utilizalole for guiding said upper curtain l3. AS shown in Figs. 11 and 2, a cover member [18 is secured to the bar d, this member being utilizable ior partially enclosing the roller l5 and associated parts. The lower curtain id is wound upon a horizontal roller 59 supported by end brackets 2d suitably held in @1601 position lnterlorly or the base i. The end brackets 2E9 also support a horizontal idler roller 20 cooperative with the lower curtain id as shown in 2. Disposed above the roller (19 and suitably held in fixed position is a light shield Zia which extends trans versely across the base i for the purpose of preventing the passage or light into engagement with the hereinafter described light-sensitive surface.

in order that the jack. screws 9 may be rotated at exactly the same speed and in the same direction, I have provided, in accordance with the invention of said pending application, a combined motor-manual control arrangement of novel character as hereinaiter described.

Thus, as shown in Figs. 1, 2 and l -the iront horizontal surface lb or the base i carries loear= lugs for and supports a plurality of spaced vertical stub shafts 26, ill, 2t 29 and 3d, these shafts depending into the hollow interior of the base i and having secured thereto the respective pinions 25a, 26a, filo, 28a, 29a and a. Further, as shown, the lower end of each jack screw 8, interiorly of said base H, has a pinion 9a secured thereto. All of the pinions just referred to are duplicates of each other and, as illustrated, the arrangement is such that the pinion 21a meshes with the pinion 26a, which meshes with the pinion 25a, the latter, in turn, meshing with the jack screw pinion 9a at the left, Fig. 4. Similarly, the

pinion 28a meshes with the pinion 29a which meshes with the pinion 306, the latter, in turn, meshing with the jack screw pinion So at the right, Fig. 4.

Referring to Fig. 2, the front vertical wall of the base i is shown as supporting a bracket ill which carries a lower bearing Ma for a vertical shaft 32 having an upper bearing at the aforesaid surface lb, the shaft 32 being spaced substantially equi-distantly from the above noted stub shafts 2i and 23. The shaft 32, interiorly of the hollow base i carries a pinion 32a which is a duplicate of the various pinions 2601, Ala. etc, said pinion 32o meshing with the aforesaid pinions tier, 2% as shown in Fig. 4. The shaft 532 extends above the aforesaid horizontal sunface to and carries a circular micrometer dish 35% cooperative with a fixed pointer member M, Fig. 4.

The lower end of the shaft 32 carries a worm wheel 35, Fig. d, with which meshes a worm 36 secured to a horizontal shalt ill suitably supported in a bearing formed by the aforesaid bracket 3i and in other bearings as hereinafter described.

One end of this shaft til extends beyond the base i and-carries a pulley 38 which is driven by an endless belt 39 driven, in turn, by a pulley til carried by the armature shaft of an electric motor M. The other end of said shaft ill terminates interiorly oi the hollow base i and carries a gear 30 which meshes with a gear d2 carried by a suitably supported shalt at, Fig. i. Disposed in a bearing formed in the horizontal surface lb is a shaft which carries an operating hand wheel id, this shaft last named being operatively connected to the aforesaid shaft 53 by an endless chain fill), or equivalent.

It is highly desirable, in accordance with the invention, that backlash and lost motion be largely or entirely eliminated from the gear trains between the pinion 32a and the respective pinions So of the jack screws To this end, as shovm, the pinious 25a, Ella, 28a and the may be constructed as illustrated in Figs. 7 and 8 in connection with the pinion 280;. That is, each or said pinions, at the periphery thereof, may be provided with a peripheral, circular recess 36 in which is received a gear ring A l having elongated, arcuate slots 68 alined with the respective threaded passages 39 formed in said pinion tile. Extending through each slot it) and threaded into the adjacent passage Gil is a screw Sit. .is will he understood, the teeth of the gear ring ll and those of the pinion 28a correspond with each other.

With the parts positioned as shown in 4-, it will be understood that the four screws dd may be loosened whereupon the gear ring ll may be moved to slight extent on and circumfereutially of the pinion 280 18y so doing, lost motion is eliminated between the pinions 229a, 532a and the connecting pinion 2830. (including its gear ring ll). Then, by tightening said screws tilt, the gear ring ll is clamped in its adjusted position to the pinill ion 28a. The gear teeth of said pinion 28d and as the gear ring 4'1, after adjustment of the latter has been effected, are related as shown by the full and broken lines in Fig. 8 and, because thus related, backlash and lost motion between the pinions 29a, 32a and the interconnecting pinion 28a are substantially entirely eliminated.

As will readily be understood, corresponding adjustments effected on the gear rings 41 of the respective pinions 25a, 21a and 30a results in the elimination of backlash and lost motion between the pinion 32a and the two jack screw pinions 911. It results, therefore, that the position of the disk 33 necessarily reflects with extreme ac curacy the position of and all adjustments which are imparted to the jack screws 9.

As shown in Fig. 2, the upper bearing for the aforesaid shaft 32 is constituted by a member having elongated slots through which extend the respective bolts 52 securing said member 5| to the base surface lb. In generally the same manner, the bolts 53 which secure the lower bearing 31a of the shaft 32 to the bracket 3| extend through elongated slots as shown. By virtue of this adjustable arrangement, it follows that the bolts 52 and 53 may be loosened so as to permit the shaft 32 and its pinion 32a to have a limited degree of movement. Accordingly, the pinion 32a may readily take such a position that it is in proper meshing relation with respect to the pinions 21a and 28a after they have been set as described above in order to avoid backlash.

After the pinion 32a has been positioned as described immediately above and then locked in position by tightening of the bolts 52 and 53, it may be that the worm 36 is not in proper meshing relation with the worm wheel 35the latter necessarily moves with the shaft 32 and pinion 32a during the adjusting movements imparted to the pinion 320.. In order to care for this condition, if it should occur, I provide a compensating arrangement of the following character.

As shown in Fig. 4, the bearing 55 for one end of the shaft 31 is secured to the base i by bolts 56 which extend through elongated slots provided, respectively, therefor in said bearing 55. The other end of said shaft 31 is supported in a bearing arrangement 51 having a plurality of elongated slots through which extend the respective bolts 58 securing said bearing arrangement 51 to its supporting structure. Furthermore, as illustrated in Figs. 2 and 4, the bracket 3! is secured to the base I by bolts 59.

After the pinion 32a has been so adjusted as to be in proper meshing relation with the pinions 21a and 28a as described above, the various bolts 56, 58 and 59 may be loosened whereupon the shaft 31 may be moved from left to right, Fig. 2, to thereby cause the two gear wheels 36 and 35 to assume a proper meshing relation. At this time, a flat shim 3lb may be placed between the base of the bracket 3| and the adjacent surface of the base i and, then, said bolts 56, 58 and 59 may be tightened to positively maintain the gear wheel 36 in the position to which adjusted.

As shown in Fig. 4, one of the stub shafts for the pinions 25a, 26a, etc., such, for example, as-

the shaft 25 may have connected thereto a gear 59a which meshes with and drives another gear 59b secured to a shaft 590 utilizable for operating suitable mechanism 59d for counting and indicating the revolutions imparted to the shaft 25.

The aforesaid base I and its wing sections la,

la form a supporting structure to which a fixed track member 661s secured in suitable manner, as by the bolts 6|, Fig. 2. Supported by this track member 60, through the anti-friction rollers 82, is a carriage 63, Fig. 2, the length of which is somewhat less than that of the track member 60. Secured to and upstanding from each end of the carriage 63 is a bracket member 64, each of which supports a standard 65, the height of these standards being substantially the same asthe combined height of the aforesaid base I and wing sections 6, and said standards 65, at the top thereof, being connected together by a horizontal member 66. These standards 65 and their horizontal connecting member 66 form a structure which extends vertically in spaced relation with respect to the adjacent wing sections 6. For guiding and steadying purposes, it is desirable that a plurality of horizontal members 61 be secured to the connecting member 66, these members 61 slidably gripping the above described bar 4 to which the wing sections 6 are secured.

In the form of the invention herein illustrated, the track member 60 extends to the right, when the machine is positioned as in Fig. 1, and the end of said track member at the right has an upstanding standard 68 secured thereto, this standard, as shown in Fig. 6, supporting a housing 69 forming end bearings for a drive shaft i0 and a screw shaft H. Rotatable with these shafts iii and II and disposed within the housing 69 are the respective gears 72 and i3 which are disposed in meshing relation, the gear 73 comprising a ring 13a corresponding with and operating the same as the ring gear 41 for removing backlash.

The screw shaft li extends from right to left, Fig. 6, horizontally above the carriage 63 and is disposed in a passage in that bracket 64 at the right of the machine, when viewed from the front, said passage being larger than the screw shaft II, and free from threads. At its end remote from the housing 69, the screw shaft H has a rotatable bearing in a bracket M fixed to the upper surface of a section id of the base i, Fig. 2. For purposes of accurate adjustment, it is desirable that the carriage 63 support another bracket 15, Fig. 6, which supports a pair of internally threaded nut devices l6 through which the screw shaft H extends and to which said shaft is threaded, these nut devices 716, as well understood in the photocomposing machine art, coacting with said screw shaft to prevent whip and backlash.

The drive shaft extends from right to left, Fig. 6, and has bearing engagement with surfaces of the adjacent base wing section la. Said shaft 10, at its end remote from the housing 69, terminates in a spiral gear 1611 which meshes with a spiral gear 16b carried by one end of a shaft 160 mounted in bearings formed in a bracket secured to the interior surface of said last named wing section la. The other end of the shaft 160 carries a spiral gear 16c which meshes with a spiral gear 16; secured at one end of a stub shaft 11 mounted in a bearing in the aforesaid wing section la. By the use of takeup means 16h, Fig. 6, coactable with their engaging spiral gears 'lBa and 167, backlash isremoved from the gear connection between the shafts 11 and 10.

- As indicated in Figs. 1 and 6 and as more fully disclosed in U. S. Letters Patent No. 2,174,726, the stub shaft 11 has secured thereto a pulley 18 Hill tit!) lib lid

with which coacts an endless belt l9 disposed in driving relation on a second pulley 80 secured to the armature shaft of an electric motor Ml suitably'secured to said wing section la.

The pulley and belt mechanism just described is disposed interiorly of a fixed housing 8i which supports suitable counter mechanism 8i geared to the stub shaft ll. As shown in Fig. l, a housing 89 is disposed at the free end of said' stub shaft 11, this housing supporting a shaft which carries a hand wheel 86, said last named shaft being suitably connected by pulley and belt mechanism to the stub shaft ll which, as shown, also carries a micrometer wheel 95.

In the form of the invention herein shown, a pivoted backboard B is utilized for the reception of the press plate, sensitized member or lightsensitive surface or member 245i. This backboard B is positioned between the standards t t5 and, as-hereinafter described. is adapted to occupy either a vertical or horizontal position.

As herein illustrated, the backboard B comprises a rectangular frame formed from vertical side members iilli, no and the horizontal top and bottom members ltl, liii, said frame being braced in any suitable manner. As shown, the free end of the backboard B may carry support ing legs Hi5 each of which may terminate in a roller I06, Fig. 2. Further, the rear surface of the backboard B preferably carries a handle member utllizable for lowering and raising said backboard. Still further, as described in U. S.

Letters Patent No. 2,174,726, said rear surface of the backboard 16 carries a pivoted lever having an actuating handle. Pivoted to opposite ends of this lever are links which terminate, respectively, in rods ii ll guided for horizontal movement by a bracket M2, Figs. 14 and 15.

Suitably secured to the rear surface of the backboard B and at the respective opposite sides thereof are the brackets M3, Figs. 14 and 15, which extend at right angles to the operative surface of said backboard B and each of which terminates in a lateral section lite, each lateral section lit, if desired, having a bolt, not shown, adjustably threaded therethrough. Each bracket M3 is formed with a transverse passage, these passages being alined with the respective passages of the aforesaid brackets Hi2. It follows, therefore, that each rod M is readily slidable in the passage through its associated brackets i l2 and the passage i 13b in the adjacent bracket [1 02.

As shown in Fig. 2, the aforesaid frame of the backboard E has a supporting structure M6 secured thereto in suitable manner, this supporting structure being formed from fibre or other suitable material and supporting an outer sur= face ill formed from hard rubber, or equivalent, to which the light-sensitive member is suitably secured.

Secured in horizontal alinement to. the bottom frame member Hill .of the backboard are a plurality of brackets M8. As shown in ill, the two brackets at the left of the backboard B support a horizontally disposed axle member ill), the two brackets at the right of said backboard B support a horizontal axle member Mill, and the three brackets centrally of said backboard support a horizontal axle member [120.

As clearly appears, the outer respective ends of the axle members M9 and 1% are received in passages formed, respectively, in vertically disposed members 622, the outer end of each axle member no and 0% preferably having a locking nut threaded thereto. For purposes of ready alinement, it is desirable that the aforesaid passages in the members B22 be formed substantially larger than the ends of the axle members H9, 620 and that blocks 824 be suitably secured to the respective lower ends of said members I 22, each of these blocks having a passage which snugly receives the end of the adjacent axle member H9 or 20 and said blocks being ad- .iustable on the lower ends of said members 622 so that the respective passages thereof may accurately be alined with the axle members N9, M0, respectively.

As shown in Figs. 4 and 9, the carriage 63 supports an upwardly-extending bracket I26 having a flat upper surface upon which rests a collar B26 secured to the aforesaid axle member I. Ac cordingly, as will be understood, the bracket 925 serves as a support for the backboard B through the instrumentality of the axle member 25 and associated parts.

As illustrated in Figs. 2 and 13, the axle member M9 supports a spiral spring in, one end file of which engages the rear surface of the backboard B and the other end [12'lb of which is seecured to a lug H28 having a slotted outer end in which is secured the upper end of a lever 629 pivoted at no to a bracket l3! supported by'the carriage 6d. 1

As herein disclosed, the axle member no supports a similar spiral spring arrangement and the axle member 02H supports a pair of said spiral spring arrangements.

When the backboard i is in its vertical position, the aforesaid spiral springs iii are unwound or substantially so. However, when said backboard is manually lowered toward and to its horizontal position, these springs iii?! are automatically wound or energized. Therefore, as will readily be understood, said springs it! serve to counterbalance and cushion movement of said backboard l5 As hereinafter described, the backboard B is adapted to be moved either toward or from the hereinbefore described supporting frame F; To this end, each of the standards G5 supports an adjusting mechanism utilizable for moving the backboard B to and fro as just stated.

in accordance with this phase of the invention, the standard at the left of the machine as viewed when facing the front thereof has fixed thereto an upper block i322 and a corresponding lower block, these blocks supporting a fixed member i136, Figs. 14 and i5. Suitably secured, as by bolts, to the fixed member (13 are the upper and lower key members E36 each being cut away as indicated at i360: and the cut-away sections be ing disposed in vertical alinernent so as to receive the aforesaid vertical member 0222 which is adapted to be moved, while held vertical, toward or from the aforesaid supporting frame F. Slidable horizontally on each key 636 is a block G38, these blocks being secured to said member i222 by suitable bolts. Above the upper block H38, the vertical member i222 has a member 039 secured thereto by suitable bolts, this member 139 carrying a lateral socket member adapted, when the backboard B is in vertical position, to be in alinement with the path of movement of the aforesaid rod ill.

Pivoted at M2 to the fixed member i345, adjacent the lower end thereof, is a lever its having its outer end connected by a pivot pin Md to a strap member M5, one end of the pivot pin ltd being operatively related to an elongated slot 122a formed in the lower end of the aforesaid vertical member I22. The strap member I45 extends in a vertical direction and is disposed flatwise against the vertical member I22. At its upper end, said strap member I45 carries a pivot pin I46 on which a lever I" is loosely supported, the latter being pivoted to the fixed member I34 by a pivot pin I49, and the pin I46 being operatively related to an elongated slot I22b formed in the upper end. of the vertical member I22.

As shown in Fig. 2, there is connected to the lever I 43 an adjustable link arrangement I49 adapted to partake of. pivotal movement, this link arrangement being connected to an arm I56 oscillatable with a horizontal shaft I5I mounted in bearings I52 supported by the aforesaid carriage 63.

As stated above, each of the standards 65 supports an adjusting mechanism for shifting the backboard B in the manner described. Inasmuch as the adjusting mechanism for the other standard 65 is a duplicate of the one just described, this description will not be repeated and, on the drawings, duplicate reference characters will be used for the designation of corresponding parts.

Accordingly, in .view ofv the description given above, it will be understood that the shaft I 5| carries two arms I50 which, through the described mechanisms, impart to and fro movement to the backboard B. For imparting rotatable movement to this shaft I5I, there may be utilized an arrangement of the character shown in Figs. 9, 11 and 12 wherein the shaft I5I is shown as carrying a disk I53 which cooperates with a second disk I54 of generally similar configuration, the disk I54 being mounted on a shaft which extends from a box I 55 containing suitable gear reduction mechanism, power to which is delivered by a shaft I55a carrying a pulley I56 engaged byan endless belt I57 driven by a second pulley I58 mounted on the armature shaft of. a suitable electrical motor M2 mounted in suitable manner on an extension of the carriage 63.

As illustrated in Figs. 11 and 12, the disks I53, i54 are provided, respectively, with gear segments I53a, I54a whereby power is transmitted from the disk I54 to the disk I53.

It is desirable that suitable shock-absorbing mechanism be provided for cushioning the impact transmitted from the disk I54 to the disk I53 when power is applied to said disk I54. A preferred form of such shock-absorbing mechanism is shown in Figs. 11 and 12.

Thus, on supports I59, I60 extending laterally from the disk I 53 are mounted the respective levers I6I, I62 which are engaged, respectively, by springs I63, I64, each spring seating against a member I65 fixed to the disk I53 and each spring normally holding its associated lever in engagement with a stop I66. These springs are relatively heavy so that each of them absorbs a large amount of the instantaneous power of the motor M2 at the instant that a driving connection is established between the disks I54 and I53. The disk I54 is mounted on a shaft I67 which extends from the aforesaid gear box I55. Secured to an extension of this shaft is a. collar I66 having an actuating lug I69 carried thereby and projecting therefrom.

With the various parts positioned as shown in Fig. 11, the backboard B is in its advanced position toward the printing plate. If it becomes desirable to move said backboard toward the rear of the machine, the motor M2 is energized in the manner hereinafter described to cause the disk I54 and its actuating lug I69 to move in a clock- Eventually, as the disk I64 moves in the direction last described, the inclined surface I69a of the actuating lug I69 comes into engagement with the curved surface I6Ia of the lever I6I and moves said lever I 6| slightly, as a distance of .010 of an inch more or less, in a counterclockwise direction, Fig. 11, with resultant compression of the spring I63 and absorption of shock. After said lever I6I has moved approximately the distance just described, the gear tooth I54b of the disk I54 comes into engagement with the gear tooth I530 of the disk I53. Thereupon, the teeth of the gear segment I54a. positively engage the teeth of the gear segment I530 to move the disk I53 in a counter-clockwise direction, Fig. 11.

At each end of the gear segment I54a, the material of the disk I54 is cut away to form the clearance passages I54c'and I54d, the length of these passages being approximately one-half the length of the curved sector I53?) of the disk I53. Therefore, with the disk I54 positioned as shown by the broken lines of Fig. 11when movement of the disk I53 in a counter-clockwise direction, Fig, 11, is just being initiated--there is clearance space in the disk I54 for the material defining the rear surface of the sector i531) of the disk I54.

Movement of the disk I53 in a counterclockwise direction, Fig. 11, under the control. of the disk I54, continues until the two gear segments I 53a, I54a are disengaged. At this time, a limit switch as hereinafter described opens the circuit of the motor M2 and, also at this time, the disk I53 becomes stationary by reason of the fact that the curved sector i53d thereof assumes a position wherein it is concentric with respect to the shaft I61 and. closely adjacent the periphery of the disk I54. Further, when the disk I53 becomes stationary as just described, the backboard B is in its retracted position removed from the printing plate. Immediately after the circuit of the motor M2 is opened as just described, the disk I54 coasts approximately to the position shown by the broken lines in Fig. 12. When the backboard B is to be moved toward the front of the machine, an operation is performed which is the reverse of that described above. That is, the motor M2 is energized in the manner hereinafter described to cause the disk I54 and its actuating lug I69 to move in a counter-clockwise direction, Fig. 12, from the broken line representation of the parts.

As the two disks I53 and I54 are positioned in Fig. 12, the curved sector I53d of the disk I53 is positioned as shown and as described above. Therefore, as the disk I54 starts to move in a counter-clockwise direction from the broken line position thereof shown in Fig. 12, the disk I53 necessarily remains stationary.

As the disk I54 continues to move in a counterclockwise direction as last noted, the inclined surface I69b of the actuating lug I69 comes into engagement with the curved surface I62a of the lever I62 and moves said lever I62 to slight extill tent in a clockwise direction, Fig. 12, with resultant compression oi the spring I84 and ab- 'sorption of shock. After said lever 662 has been moved slightly as Just stated, the gear tooth Mile of the disk I54 comes into engagement with the gear tooth 1532 of the disk H53. Thereupon, the teeth of the gear segment 854a positively engage the teeth of the gear segment 653a to move the disk I53 in a clockwise direction, Fig. 12. Dur= ing initial movement or said disk tilt, the clearance space i5 lc serves to prevent binding between the rear surface of the sector lStcZ and the adjacent face 01 the disk ltd.

Movement of the dish hill in a clockwise direction, Fig. l2, under the control of the dish 05d continues until the two gear segments iillo, idle, are disengaged. At this time, a-lirnit switch as hereinafter described opens the circuit of the motor Mil and, also at this time, the dish this he= comes stationary due to the fact that the curved section will thereof has again assumed a posi= tlon wherein it is concentric with respect to the shaft it'll and closely adjacent the periphery of the dish tilt. When the disl: 0533 becomes etationary as just stated, the backboard E5 is in its advanced position toward the printing plate and, immediately after the circuit of the motor M2 is opened as just descriloed, the dish not coasts to the approximate position shown by the lull lines in ii.

The supporting frame 3? previously referred to is adapted to support an adapter frame A which, in turn, is adapted to support a printing plate holder 1?, the latter serving as a support for the printing plate Pl which may he either a photo-= graphic positive or negative as desired, the ills. ness of which is to he reproduced on the sensitized surface supported by the backboard or the photo: composing machine. As shown Fig. l, a seal= ing trance ,i may he utilised for sealing the open= ing between the printing plate Pi the print= ing plat/e holder P. Alternatively, said printing plate holder may he of such dimensions that it is supported directly by the supporting frame without requiring the use of adapter frame A. All oi the construction noted immediately alcove is described in detail in U. S. Letters Patent No. all L726,

in accordance with invention, the circuits oi the hereinhefore descrihed motors lVl, Ml and M2 together with the circuit of the hereinafter described printing lamp Lo are controlled in a novel and highly desirable manner. The electrical current supply for these various circuits may he direct or alternating, or single or rnulti phase as desired. As herein shown, three-phase alternating current is thus utilized, the supply thereoi losing obtained irom the line circuit desig= hy the conductors L2 and L3, ll.

ll'tilizaole for controlling the motor M2, as the is shown in l7, the coils 361d, wt,

From the line LS, a conductor leads to one term nal of the coil Sill, this conductor 362 ineluding fixed contacts of a closed switch. 8 63. The other oi the con Sill con nested thereto a conductor 5366 which leads to the line conductor 3M including the fixed contacts oi a normally open, manually op erahle switch @onnected to the aforesaid conductor 22 hich leads the line is a conductor 3% winch leads to one of the coil 3%, this wild-WW1 396 melodies the filled contacts oi of the conductor open limit switch 301. The other terminal of the coil 300 has connected thereto a conductor 300 which leads to the line Ll by, way of a part of the conductor 304, this conductor 300 including the fixed contacts of a manually operable, normally open switch 309 and this conductor 30! also including the upper set of fixed contacts of a switch M0.

Coactable with the coil 30! is an armature 30m utillzable for moving the movable contacts of the respective conductors 3i i, tit. and tit into engagement with the respective fixed contacts of the conductors 3 it, M5 and tit.

Coactable with the coil 308 is an armature 300a utilizable for moving the movable contacts of the respective conductors til, till and till into engagement with the respective fixed contacts oi the conductors 329, on and tilt.

As illustrated, the conductors Sill and till are connected together at and to a branching conductor 23253 which leads to one terminal oi the motor M. The conductor 362 is connected to the aforesaid conductor to l. The conductors 8M and 369 are connected together at and to a branching conductor 82 3 which leads to another.

terminal or the aforesaid motor M52. The condoctors 80 3- and 3GB are connected together to common conductor 825 which leads to and is connwted to the aforesaid conductor lit-"l8. The conductors 32d and 32!] are connected together to a common conductor 826 which leads to and is connected to said conductor 82?. The condutors 3M3 and 322 connected together to a common conductor Sill which leads to and is connected to the Moresaid conductor 30. The third terminal oi the motor M2 connected thereto a conductor 328 which leads to and is con= nected to the line Connected to the aforesaid conductor e98 hetween the switch tit) and the conductor 30 3 is a conductor 829 which leads to and is connected to the conductor 3G2 hetween the limit switch 368 and the line L3. This conductor 329 includes lower set oi iii-zed contacts or the switch 3i 0 it also includes an lncandmcent lamp Slit.

generally the same manner as descrilced shove in connection wit the motor M2, coils S36 832, or equivalent, are associated with the motor The aforesaid conductor 862 (which @0333,

nected to the line has connected thereto, hetween the limit switch 383 the coil Sill, a conductor 833 which, in the manner hereinafter desciihed, is to connect line L3 to the respective coils of the motors M and Ml.

To this end, a conductor 83G is connected to said conductor 338, and this conductor 33G includes the hired contacts of a normally closed switch coo. Connected to end of the con ductor 335 remote conductor:

leads to the line conductor including contacts normally open, opcsahle switch A second conductor connected to that end 000 leads to and is connected to one tern incl the co this conductor including if e:

remo e from the conductor nected to the aforesaid conductor 338 between the switch 339 and the line L2, this conductor 342 including the fixed contacts of a normally.

open, manually operable switch 343.

Coactable with the coil 332 is an armature 332a utilizable for moving the movable contacts of the respective conductors 344, 345 and 346 into engagement with the respective fixed contacts of the conductors 341, 348 and 349.

Coactable with the coil 331 is an armature 331a utilizable for moving the movable contacts of the respective conductors 358, 351 and 352 into engagement with the respective fixed contacts of the conductors 353, 354 and 355.

As illustrated in Fig. 17, the conductors 346 and 358 are connected together at a branching conductor 356 which leads to one terminal of the motor M. The conductor 345 is connected to the aforesaid conductor 338 which leads to one terminal of the coil 332. The conductors 344 and 352 are connected together at a branching conductor 351 which leads to another terminal of said motor M2. I'he conductors 341 and 348 are connected together to a common conductor 358 which leads to and is connected to the aforesaid conductor 338. Conductors 353 and 354 are connected together to a common conductor 359 which leads to and is connected to said conductor 358. The conductors 349 and 355 are connected together to a common conductor 368 which leads to and is connected to the line L3. The third terminal of the motor M has connected thereto a conductor 361 which leads to and is connected to the line L2.

Associated with the motor M1, Fig. 1'7, in gen erally the same manner as described in connection with the motors M2 and M are.the coils 362, 363, or equivalent.

A conductor 364 is connected to the aforesaid conductor 333, this conductor 364 including the fixed contacts of a normally closed switch 365. Connected to that end of the conductor 364 remote from the conductor 333 is a conductor 366 which leads to and is connected to one terminal of the coil 363, this conductor 386 including the fixed contacts of a normally closed limit switch 361. Connected to the other terminal of the coil 363 is a conductor 368 which leads to the line L1, this conductor 368 including the fixed contacts of a normally open, manually operable switch 369.

A second conductor 318 is connected to that end of the conductor 364 remote from the conductor 333, the conductor 318 leading to and being con nected to one terminal of the coil 362, the conductor 318 including the fixed contacts of a normally closed limit switch 311. Connected to the other terminal of the coil 362 is a conductor 312 which leads to and is, connected to the aforesaid conductor 368 between the switch 369 and the line L1, the conductor 312 including the fixed contacts of a normally open manually operable switch 313. Coactable with the coil 363 is an armature 363a utilizable for moving the movable contacts of the respective conductors 314, 315 and 316 into engagement with the respective fixed contacts of the conductors 311, 318 and 319.

Coactable with the coil 362 is an armature 362a utilizable for moving the movable contacts of the respective conductors 388, 381 and 382 into engagement with the respective fixed contacts of the conductors 383, 384 and 385.

As shown, the conductors 316 and 388 are connected together at a branching conductor 386 which leadsto one terminal of the motor M1. The conductor 315 is connected to the aforesaid conductor 388 which was described as leading to one terminal of the coil 383. The conductors 314 and 382 are connected together at a branching conductor 381 which leads to another terminal of said motor M1. The conductors 311 and 318 are connected together to a common conductor 388 which leads to and is connected to the aforesaid conductor 368 between the line L2 and the connection thereto of the conductor 312. The conductors 383 and 384 are connected together to a common conductor 388a which leads to'and is connected to said conductor 388. The conductors 319 and 385 are connected together to a com mon conductor 389 which leads to and is connected to the line L3. The third terminal of the motor M1 has connected thereto a conductor 398 which leads to and is connected to the line L2.

\ Referring to Fig. 17, the fixed contacts of a switch 488 have conductors 481, 482 connected, respectively, thereto. As shown in Fig. 18, the conductor 481 is connected to a contact 483a of a switch 483, and the conductor 482 is connected to a contact 484b of a switch 484. (For purposes of ready understanding, the sheet of drawing on which Fig. 18 appears should be placed at the right of and in alinement with the sheet of drawing on which Fig. 17 appears.)

The switch 483 comprises three other contacts 483b, 4830 and 483111. The contact 4831) is connected to the contact 484d of the switch 484 by a'conductor 485. The contact 4830 is connected by a conductor 486 to one terminal of a coil 481, or equivalent. The contact 483d is a dummy contact.

The switch 484 comprises five contacts 484a,-

unit, these two arms being connected to a com mon conductor 412 which leads to the line L2. As clearly appears, the contacts of the switch 483 are engageable by the arms of said switch only in pairs 483a, 4830 or 483b, 483d.

In addition to the coil 481, the circuit-controlling arrangement of Fig. 18 comprises a pair of coils 413, 414, or equivalent, coactable with an armature arrangement 415 pivoted at 416. One terminal of each of these coils 413, 414 is connected together to a common conductor 411 which is connected to a conductor 418 leading to the line L1. The other terminal of the coil 413 is connected by a conductor 419 to a terminal of the aforesaid limit switch 489. The other terminal of the coil 414 is connected by a conductor 428 to a terminal of the aforesaid limit switch 411.

The armature arrangement 415 of the coil 413 is utilizable for moving the movable contacts of the respective conductors 421, 422, 423 and 424 into engagement with the respective fixed contacts of the conductors 425, 426, 421 and 428.

The armature arrangement 415 of the coil 414 is utilizable for moving the movable contacts of the respective conductors 429, 438, 431 and 432 into engagement with the respective fixed contacts of the conductors 433, 434, 435 and 436.

As shown in Fig. 18, the conductor 421 has the conductor 424 connected thereto, said conductor 421 being connected to the aforesaid conductor 412 which leads to the line L2. The conductor 422 has the conductor 423 connected thereto, and

said conductor 422 is connected to the aforesaid conductor 4% which, ,as stated, leads to the line Ll.

The conductor 425 leads to and is connected to the conductor 408. The conductor 425 leads to the terminal '1! of a timer motor M4. The conductor 42? leads to the terminal T2 of said motor M4. The conductor 428 leads to a conductor 431 which is connected to the terminal T4 of said motor M4. The terminal T3 oi said motor M4 is connected to the aforesaid conductor 2 by a conductor 43in.

The conductor 432 has the conductor 430 connected thereto, said conductor on leading to and being connected to the aforesaid conductor 492 which leads to the line L2. The conductor 43i has the conductor 429 connected thereto, said conductor 4: leading to and being connected to the conductor 8 which leads to the line Ll.

The conductor 435 leads to and is connected to the aforesaid conductor did. The conductor 435 leads to and is connected to the conductor 626. The conductor 434 leads to and is connected to the conductor 42?. The conductor 33d leads to and is connected to the aforesaid conductor @317.

As hereinloefore stated, one terminal of the coil Ml is connected to the contact this of the switch Mill by a conductor no. The other terminal of this coil 4011 is connected to the conductor 335 by a conductor 438. The coil dill has coactable therewith an armature cilia utilisable for moving the movable contacts oi. the aforesaid conductors can, 432 into engagement with the respective fixed contacts or conductors 439, 44@ which lead to and are connected to the electrodes of the lamp La, this lamp lacing oi the arc type familiar to those skilled in the art for effecting the printing opera tions in connection with photocomposing ma= chines.

The motor Mt is the familiar type of timer motor utilizable for operating mechanism for timing the duration of the periods of exposure, i. e., the periods during which the sensitized surface is illuminated by the printing lamp. A motor of this type includes a field winding between the contacts Ti and T3, and another field winding between the contacts T l and T2. As shown, the armature oi the motor Md is geared to a wheel Ml which carries an arm M2 adapted to engage either the limit switch Gilli or the limit switch ill i. As will be hereinafter described, the limit switch Mill is stationary whereas the position of the limit switch 4| is adjustable so as to vary the duration of the timing periods.

The operation is as follows:

preliminarily, as described in detail in U. S. Letters Patent No. 217 5326, the operator secures to the supporting irame ll either an adapter frame A and an associated printing plate holder P, or a printing plate holder P alone. Then, after a suitable sensitized surface has been se cured to the backboard e, the latter is elevated by manual action to its vertical position where upon the rods fill are actuated to positively se-= cure the upper end of said backboard E to the respective vertical members 122, the lower end of said backboard B already being positively retained to said vertical members 622 by the respective axle members M9 and [12d Upon completion oi the foregoing, the backboard E is in its rear vertical position with the sensitized surface thereof facing the adjacent vertically disposed printing plate and spaced therefrom.

At this time, it becomes necessary to adjust of said switch 333, the coil 332, conductor 333 including the contacts of the normally closed limit switch 331, conductor 334 including the contacts 01. the normally closed switch 333, conductor 333, and thence to the line L3 by way of the conductor 302 which includes the contacts of the closed limit switch 303. When the coil 332 is thus energized, it attracts its armature 332a and closes the movable contacts oi! the conductors 344, 345 and 346 onto the respective fixed contacts oi the conductors 341, 343 and 343.

In so doing, there is established a locking circuit for holding the coil s32 energized after the switch 3353 automatically opens after release thereof by the operator. This locking circuit extends from the line Ll by way of the conductor 338, conductor the, conductor 3%, conductor 345, the winding of the coil Z332, conductor 333 including the contacts of the normally closed limit switch 33W, conductor use including the contacts oi the normally closed switch 385, conductor 3333, and thence to the line L3 by way of the conductor 5332 which includes the contacts of the closed limit switch 3633.

As stated, one terminal or the motor M is permanently closed to the line L2 by the conductor 36G. The above noted closure oi the armature @3202 causes the conductors 3%, 343 to be closed to the line Lil by way of the conductors 365i and 368. At the same time, the conductors 85E, 3% are closed to the line Ll by way of the conductors t ll, 358 and 33d.

Accordingly, in response to closure of its operating circuit as just described, the armature oi the motor ll/l rotates in the proper direction to cause upward movement oi the printing frame F under the direct control oi the jack screws 4. when the frame F has been elevated approximately to its intended position, the stop switch Figs. 1 and i7 is operated to open the alcove described holding circuit for the coil 332. In response to opening of this circuit, said coil 332 is deenergized with consequent release of its armature 332a whereby the operating circuit oi the motor M is opened. In this way, operation oi said motor M is discontinued and, at this time, by manipulation of the hand wheel tilt, the desired elevated position oi the supporting frame F may be attained; with precision and 'nicety.

If it had been necessary to lower the support ing frame F rather than to raise the same, the switch 368, Figs. 11 and it, is closed to thereby complete through the coil 836 a circuit which leads from the line LE1, by way of conductor 338, conductor 3 32 including the contacts of said switch 8&3, the coil 323i, conductor including the contacts of the normally closed limit switch 341i, conductor 836 including the contacts oi the normally closed switch conductor 338, and thence to the line L3 Toy way oi the conductor Still which includes the contacts of the closed limit switch When the coil 233i is thus energized, it attracts its armature 33in and closes the movahle contacts of the conductors 35d, and onto the respective lined con tacts oi the conductors $53, 35 and tits.

A secured to the out oer 553 In so doing, there is established a locking circuit for holding the coil 33l energized after the switch 313 opens when manually released. This locking circuit extends from the line L! by way of the conductor 338, conductor 358, conductor 359, conductor 354, conductor 35!, the winding of the coil 33!, conductor 340 including the contacts of the normally closed limit switch 34!, conductor 33! including the contacts of the normally closed switch 335, conductor 333, and thence to the line L3 by way of the conductor 3B7 which includes the contacts of the closed limit switch 393.

As stated, one terminal of the motor M is permanently closed to the line L2 by the condoctor 355. The above noted closure of the armature 335a causes the conductors 356, 356 to ice closed to the line Ll by way of the concluctors 353, 359, 353 and 333. At the same time, the conductors till, 332, are closed to the line L3 by way of the conductors 355 and 363.

Accordingly, in response to closure of its operating circuit, the armature of the motor M rotates in proper direction, the opposite of that described above, to cause downward movement of the printing frame F under the direct control of the jack screws 9. When the frame F has been lowered approximately to its intended position, the stop switch 335, Figs. 1 and l'l, is operated to open the above described holding circuit for the coil In response to opening of this circuit, said coil 331i is deenergized with consequent release oi its armature 335a whereby the operating circuit of the motor M is opened.

" Thus, operation oisaicl motor M is discontinued and, at this time, or manipulation of the hand wheel the desired lowered position of the supporting frame 35 may readily be attained.

The limit switches and t ll, Figs. 1, leancl 17, are provided so that excessive upward or downward movements of the supporting frame F may be avoided. it the operator neglects to open the stop switch while the supporthig frame i is traveling upwardly under control of the motor til, the upper section Fig. 3, of the slide l2 engages the movable member 554 or" the limit switch which is fixed to the standard 2a to thereby open the holding circuit of the coil 33? at the fixed contacts oi the limit switch in so doing, the coil 5332 is deenergised and there is resultant discontinuation of the operation or motor M. In case the supporting frame F is moving downwardly and the operator neglects to open the stop switch 33%, a member l -52, Fig. 3,

i engages the movable momor the limit switch S ll which is fused to the standard to to o sen the fixed contacts thereof whereby the holding circuit of the coil 336 is deenergized with consequent discontinuation of oporation oi the motor lei.

After the printing plate Pl has been moved to a desired position under control oi the supporting frame 5 in the manner described above and while the backboard remains in rear vertical position, it

-hecomes necessary to shift said backboard 3 either toward the right or left so as to bring a desired section of the sensitized surface opposite said printing plate To this end, if the hackboard B is to be moved toward the right, when viewed as in Fig. l, the switch 359, Figs. 1 and 17, is closed to thereby complete through the coil 363 a circuit which leads from the line Ll, conductor 3% including the contacts of said switch 359, the coil 363, conductor 3655 including the contacts of the normally closed limit switch 351, conductor 384 including the contacts oi the normally closed switch 385, conductor 333 and thence to the'line L3 by way or the conductor 362 which includes the contacts of the closed switch 303. When the coil 363 is thus energized, it attracts the armature 363a and closes the movable contacts of the conductors 316, 315 and 336 onto the respective, fixed contacts of the conductors all, are and 3715.

In so doing, there is established a locking cit-=- cuit for holding the coil tilt energized after the switch 3&3 opens upon manual release thereof, This locking circuit extends from the line Ll by way of the conductor tilt, conductor see, conductor are, conductor Slit-l, the winding oi. the coil 353, conductor 3% including the fixed coritects of the normally closed limit switch till, conductor set including the contacts of the normally closed switch tell, conductor 2323, and thence to the line L3 by way of the conductor til? which includes the contacts of the closed limit switch As stated, one terminal or the motor Ml is per= manently closed to the line L2 by the conductor 3%. The above noted closure of the armattue 353a causes the conductors tit to he closed to the line by way of the conductors and At the same time, the conductors 38?, til are closed at the line Ll oy way of the conductors till, 3233 and Accordingly, in response to closure oi its op crating circuit as just described, the armature oi the motor Ml rotates the proper direction to cause movement oi the backboard E toward the right, as viewed in Fig. 1, under the direct control of the operating screw shaft ii. When the backboard B has been moved approximately tot its intended position, the stop switch is manually operated to open the above described holding circuit for the coil In response to opening oi this circuit, said coil is deenersized with consequent release of its amature whereby the operating circuit of the motor Ml is opened. As a result, operation oi said motor it'll is discontinued and, at this time, by manipulation of the hand wheel the desired position of the backboard B may be attained with precision.

if it had been necessary to move the backboard toward the leit as viewed in Fig. l, the switch tilt, Figs. 1 and it, is closed to thereby complete through the coil 362 a circuit which leads from the line Ll, by way of conductor tilt, conductor m2 including the contacts of said switch tit, the winding of coil conductor illil including the contacts or; the normally closed limit switch till, conductor including" the contacts of the norreally closed switch conductor and thence to the line L3 by way of the conductor see which includes the contacts or" the closed limit switch When the coil is thus energized, it attracts its armature 362a. and closes the movable contacts oi conductors soc, till and onto the respective fixed contacts oi the conductors 333, 3M and In so doing, there is established a locking ctrcuit for holding the coil energmed alter the switch 3% opens after the pressure thereon is released. This looking circuit extends from the line Ll by way of the conductor 383, conductor 38$, conductor 38%, conductor Sti l, conductor 385, the winding of the coil 382, conductor tilt including the contacts of the normally closed limit switch 311i, conductor 3% including the contacts of the normally closed switch 333, con- Eli ductor 333 and thence to the line L3 by way of 35 

